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Abstract:

A disposable wearable infusion device comprises a body arranged to be
adhered to a patient's skin and to receive a cannula to extend from the
infusion device to beneath the patient's skin, a reservoir for holding a
liquid medicament to be infused into the patient, and a pump that
displaces a volume of the liquid medicament from the reservoir to the
cannula for delivery to the patient. The body has a port aligned with the
cannula that permits the cannula to assume a deployed position to extend
from the infusion device to beneath the patient's skin. The device
further comprises a cover that blocks the port to preclude direct access
to the cannula through the port after deployment.

Claims:

1. A disposable wearable infusion device comprising:a body arranged to be
adhered to a patient's skin and to receive a cannula to extend from the
infusion device to beneath the patient's skin;a reservoir for holding a
liquid medicament to be infused into the patient;a pump that displaces a
volume of the liquid medicament from the reservoir to the cannula for
delivery to the patient,the body having a port aligned with the cannula
and enabling the cannula to assume a deployed position to extend from the
infusion device to beneath the patient's skin; anda cover that blocks the
port to preclude direct access to the cannula through the port after
deployment.

2. The device of claim 1, wherein the cover blocks the port subsequent to
deployment of the cannula.

3. The device of claim 2, wherein the covers blocks the port as a response
to deployment of the cannula.

4. The device of claim 2, wherein the cannula is arranged to be deployed
with a drive needle that extends through the port and carries the cannula
into the deployed position and wherein the cover is arranged to block the
port upon withdrawal of the needle from the port after deployment of the
cannula.

5. The device of claim 4, wherein the port cover is arranged to be held
away from the port by the needle prior to cannula deployment.

6. The device of claim 5, wherein the port cover is formed of resilient
material and is arranged to spring over and block the port responsive to
the drive needle being withdrawn from the port.

7. The device of claim 1, wherein the device body includes a cavity, and
wherein the device further includes a cannula carrier including the port,
wherein the cannula carrier is arranged to be received within the device
cavity when the cannula is deployed, and wherein the cannula carrier
includes the cover.

8. The device of claim 7, wherein the cannula is arranged to be deployed
with a drive needle that carries the cannula carrier and the cannula into
the deployed position and wherein the cover is arranged to block the port
upon withdrawal of the needle from the cannula carrier after deployment
of the cannula.

9. The device of claim 8, wherein the port cover is arranged to be
displaced from the port by the needle prior to cannula deployment.

10. The device of claim 9, wherein the port cover is formed of resilient
material and is arranged to spring over and block the port responsive to
the drive needle being withdrawn from the port.

11. A disposable wearable infusion device comprising:a body arranged to be
adhered to a patient's skin, the body having a cavity;a cannula assembly
deployed within the device body and including a cannula carrier received
within the body cavity and a cannula extending from the carrier to being
beneath the patient's skin, wherein the cannula carrier includes a port
aligned with the cannula that facilitates deployment of the cannula
assembly;a reservoir for holding a liquid medicament to be infused into
the patient;a pump that displaces a volume of the liquid medicament from
the reservoir to the cannula for delivery to the patient, anda port cover
that blocks the port to preclude direct access to the cannula through the
port after deployment.

12. The device of claim 11, wherein the cannula carrier includes the port
cover.

13. The device of claim 12, wherein the cannula is arranged to be deployed
with a drive needle that extends through the port and carries the cannula
carrier and the cannula into the deployed position and wherein the cover
is arranged to block the port upon withdrawal of the needle from the
cannula carrier after deployment of the cannula.

14. The device of claim 13, wherein the port cover is arranged to be
displaced from the port by the needle prior to cannula deployment.

15. The device of claim 14, wherein the port cover is formed of resilient
material and is arranged to spring over and block the port responsive to
the drive needle being withdrawn from the port.

16. A cannula assembly for use within a disposable infusion device,
comprising:a cannula carrier received within the body cavity;a cannula
extending from carrier for being beneath the patient's skin, wherein the
cannula carrier includes a port aligned with the cannula that facilitate
deployment of the cannula assembly within the device; anda port cover
that blocks the port to preclude direct access to the cannula through the
port after deployment.

17. The assembly of claim 16, wherein the cannula assembly is arranged to
be deployed with a drive needle that extends through the port and carries
the cannula carrier and the cannula into the deployed position within the
infusion device, and wherein the cover is arranged to block the port upon
withdrawal of the needle from the cannula carrier after deployment of the
cannula assembly.

18. The device of claim 17, wherein the port cover is arranged to be
displaced from the port by the needle prior to cannula deployment.

19. The device of claim 18, wherein the port cover is formed of resilient
material and is arranged to spring over and block the port responsive to
the drive needle being withdrawn from the port.

Description:

BACKGROUND OF THE INVENTION

[0001]The present invention relates to infusion devices and more
particularly to such devices that enable liquid medicaments to be
conveniently and safely self-administered by a patient.

[0002]Administration of insulin has traditionally been accomplished using
a syringe. Recently, needle carrying pen-like devices have also been
employed for this purpose. Both forms of insulin administration require
the patients to stick themselves each time they inject insulin, often
many times a day. Thus, these traditional forms of insulin administration
have been a rather pervasive intrusion in the lives and routines of the
patient's who have had to adopt and employ them.

[0003]More recently, insulin pumps attached by tubing to an infusion set
mounted on the patient's skin have been developed as an alternative form
of insulin administration. Such pumps may be controlled by a programmable
remote electronic system employing short range radio communication
between a control device and electronics that control the pump. While
such devices may involve fewer needle sticks, they are expensive to
manufacture. They are also complex to operate and cumbersome and awkward
to wear. Further, the cost of such devices can be many times the daily
expense of using a traditional injection means such as a syringe or an
insulin pen.

[0004]Devices of the type mentioned above also require a significant
amount of training to control and thus use the devices. Great care in
programming the devices is required because the pumps generally carry
sufficient insulin to last a few days. Improper programming or general
operation of the pumps can result in delivery of an excessive amount
insulin which can be very dangerous and even fatal.

[0005]Many patients are also reluctant to wear a pump device because they
can be socially awkward. The devices are generally quite noticeable and
can be as large as a pager. Adding to their awkwardness is their
attachment to the outside of the patients clothes and the need for a
catheter like tubing set running from the device to an infusion set
located on the patient's body. Besides being obvious and perhaps
embarrassing, wearing such a device can also be a serious impediment to
many activities such as swimming, bathing, athletic activities, and many
activities such as sun bathing where portions of the patient's body are
necessarily uncovered.

[0006]In view of the above, a more cost effective and simple device has
been proposed whereby an injection system is discreetly attached directly
to the skin of the patient. The device may be attached to the patient
under the patient's clothing to deliver insulin into the patient by the
manual pumping of small doses of insulin out the distal end of a
temporarily indwelling cannula that is made a part of the pump device.
The cannula may be made a part of the drug delivery device before, during
or after the attachment of the drug delivery device to the skin of the
patient. The device may be made quite small and, when worn under the
clothes, entirely unnoticeable in most social situations. It may still
carry sufficient insulin to last a patient several days. It can be
colored to blend naturally with the patient's skin color so as not to be
noticeable when the patient's skin is exposed. As a result, insulin for
several days may be carried by the patient discreetly, and conveniently
applied in small dosages after only a single needle stick. For a more
complete description of devices of this type, reference may be had to
co-pending application Ser. No. 11/906,130, filed on Sep. 28, 2007 for
DISPOSABLE INFUSION DEVICE WITH DUAL VALVE SYSTEM, which application is
owned by the assignee of this application and hereby incorporated herein
by reference in its entirety.

[0007]The present invention provides further improvement to the devices
disclosed in the above referenced co-pending application. More
particularly, the devices disclosed herein provide for improved patient
safety and/or convenience. For example, embodiments of the invention
provide, for example, improved sealing of the medicament, more convenient
cannula deployment, device misuse prevention, primed and dosage ready
indication and fluid path occlusion detection. These and other advantages
are addressed herein.

SUMMARY OF THE INVENTION

[0008]In one embodiment, a disposable wearable infusion device comprises a
body arranged to be adhered to a patient's skin and to receive a cannula
to extend from the infusion device to beneath the patient's skin, a
reservoir for holding a liquid medicament to be infused into the patient,
and a pump that displaces a volume of the liquid medicament from the
reservoir to the cannula for delivery to the patient. The body has a port
aligned with the cannula and enabling the cannula to assume a deployed
position to extend from the infusion device to beneath the patient's
skin, and a cover that blocks the port to preclude direct access to the
cannula through the port after deployment.

[0009]The cover may be arranged to block the port subsequent to and as a
response to deployment of the cannula. The cannula may be arranged to be
deployed with a drive needle that extends through the port and carries
the cannula into the deployed position.

[0010]The cover may be arranged to block the port upon withdrawal of the
needle from the port after deployment of the cannula. The port cover may
more particularly be arranged to be held away from the port by the needle
prior to cannula deployment. The port cover may be formed of resilient
material and arranged to spring over and block the port responsive to the
drive needle being withdrawn from the port.

[0011]The device body may include a cavity. The device may further include
a cannula carrier including the port. The cannula carrier may be arranged
to be received within the device cavity when the cannula is deployed. The
cannula carrier may include the cover.

[0012]The cannula may be arranged to be deployed with a drive needle that
carries the cannula carrier and the cannula into the deployed position.
The cover may then be arranged to block the port upon withdrawal of the
needle from the cannula carrier after deployment of the cannula.

[0013]The port cover is preferably arranged to be displaced from the port
by the needle prior to cannula deployment. The port cover may be formed
of resilient material and arranged to spring over and block the port
responsive to the drive needle being withdrawn from the port.

[0014]In another embodiment, a disposable wearable infusion device
comprises a body arranged to be adhered to a patient's skin. The body has
a cavity The device further comprises a cannula assembly deployed within
the device body. The cannula assembly includes a cannula carrier received
within the body cavity and a cannula extending from the carrier to being
beneath the patient's skin. The cannula carrier includes a port aligned
with the cannula that facilitates deployment of the cannula assembly. The
device further comprises a reservoir for holding a liquid medicament to
be infused into the patient, a pump that displaces a volume of the liquid
medicament from the reservoir to the cannula for delivery to the patient,
and a port cover that blocks the port to preclude direct access to the
cannula through the port after deployment.

[0015]The cannula carrier may include the port cover. The cannula may be
arranged to be deployed with a drive needle that extends through the port
and that carries the cannula carrier and the cannula into the deployed
position. The cover may be arranged to block the port upon withdrawal of
the needle from the cannula carrier after deployment of the cannula. The
port cover is arranged to be displaced from the port by the needle prior
to cannula deployment. The port cover is preferably formed of resilient
material and arranged to spring over and block the port responsive to the
drive needle being withdrawn from the port.

[0016]According to a further embodiment, a cannula assembly for use within
a disposable infusion device comprises a cannula carrier received within
the body cavity, a cannula extending from carrier for being beneath the
patient's skin, wherein the cannula carrier includes a port aligned with
the cannula that facilitate deployment of the cannula assembly within the
device, and a port cover that blocks the port to preclude direct access
to the cannula through the port after deployment.

[0017]The cannula assembly may be arranged to be deployed with a drive
needle that extends through the port and carries the cannula carrier and
the cannula into the deployed position within the infusion device. The
cover may be arranged to block the port upon withdrawal of the needle
from the cannula carrier after deployment of the cannula assembly. The
port cover may be arranged to be displaced from the port by the needle
prior to cannula deployment. The port cover is preferably formed of
resilient material and arranged to spring over and block the port
responsive to the drive needle being withdrawn from the port.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018]The features of the present invention which are believed to be novel
are set forth with particularity in the appended claims. The invention,
together with further features and advantages thereof, may best be
understood by making reference to the following description taken in
conjunction with the accompanying drawings, in the several figures of
which like reference numerals identify identical elements, and wherein:

[0019]FIG. 1 is a perspective view of an infusion device embodying the
present invention shown without a deployed cannula;

[0020]FIG. 2 is another perspective view of the infusion device of FIG. 1
shown with a deployed cannula;

[0022]FIG. 4 is a sectional view, in perspective, to an enlarged scale,
taken along lines 4-4 of FIG. 1, showing the actuation linkages of the
device of FIG. 1 prior to medicament dosage delivery;

[0023]FIG. 5 is another sectional view, in perspective, to an enlarged
scale, taken along lines 5-5 of FIG. 2, showing the actuation linkage
operation of the device of FIG. 1 during medicament dosage delivery;

[0024]FIG. 6 is another sectional view similar to that of FIG. 5, in
perspective, to an enlarged scale, showing the actuation linkage
operation of the device of FIG. 1 immediately after dosage delivery;

[0025]FIG. 7 is a schematic representation of the valves and pump of the
device of FIG. 1 between medicament dosage deliveries and during the
filling of the pump with the medicament;

[0026]FIG. 8 is another schematic representation of the valves and pump of
the device of FIG. 1 during medicament dosage delivery;

[0027]FIG. 9 is a sectional view, in perspective, to an enlarged scale,
showing the configuration of the valves of the device of FIG. 1 during
pump filling and prior to medicament dosage delivery;

[0028]FIG. 10 is another sectional view, in perspective, to an enlarged
scale, showing the configuration of the valves of the device of FIG. 1
during dosage delivery;

[0029]FIG. 11 is a top perspective view of the base of the device of FIG.
1 illustrating various fluid paths within the device;

[0030]FIG. 12 is a partial bottom plan view of the base of the device of
FIG. 1 to illustrate the interior of a prime indicator according to one
embodiment thereof;

[0031]FIG. 13 is a bottom plan view of the base of the device of FIG. 1
illustrating the prime indicator interior covered by a translucent cover
according to the above mentioned prime indicator embodiment;

[0032]FIG. 13A is a bottom view of the device 110 illustrating a removable
non-adhesive layer overlying an adhesive layer on the device base;

[0033]FIG. 14 is a sectional view in perspective of an occlusion detector
and lock-out according to an embodiment of the device of FIG. 1 shown
prior to an intended dosage delivery;

[0034]FIG. 15 is another sectional view in perspective of the occlusion
detector and lock-out shown during an intended dosage delivery;

[0035]FIG. 16 is another sectional view in perspective of the occlusion
detector and lock-out shown during occlusion detection and just prior to
lock-out;

[0036]FIG. 17 is a perspective view of the device of FIG. 1 and a cannula
placement assembly attached thereto ready to provide the device with a
cannula according to a still another embodiment;

[0037]FIG. 18 is a sectional view, in perspective, to an enlarged scale,
of the device and cannula placement assembly before the cannula is
deployed;

[0038]FIG. 19 is a sectional view like that of FIG. 18, showing the device
and cannula placement assembly during cannula deployment;

[0039]FIG. 20 is a sectional view like that of FIG. 18, showing the device
and cannula placement assembly after cannula deployment;

[0040]FIG. 21 is a sectional view, in perspective, of the cannula
placement assembly of FIG. 17, showing the driver prior to cannula
deployment;

[0041]FIG. 22 is a sectional view, in perspective, and to an enlarged
scale, of the cannula placement assembly of FIG. 17, showing the driver
through a plane perpendicular to the sectional plane of FIG. 21 and prior
to cannula deployment;

[0042]FIG. 23 is another sectional view similar to FIG. 22 showing the
cannula placement assembly in an enabled configuration;

[0043]FIG. 24 is a sectional view, in perspective, and to an enlarged
scale, showing the cannula placement assembly being released for
deploying a cannula;

[0044]FIG. 25 is a sectional view, similar to that of FIG. 21, showing the
cannula placement assembly during cannula deployment;

[0045]FIG. 26 is another sectional view, similar to that of FIG. 21,
showing the cannula placement assembly after cannula deployment;

[0046]FIG. 27 is a perspective view of the device and cannula placement
assembly after cannula deployment and separation of the cannula driver
from the device;

[0047]FIG. 28 is another sectional view of the cannula placement assembly
and device to an enlarged scale showing the device and driver including
details of a cannula needle port cover during cannula delivery;

[0048]FIG. 29 is a sectional view similar to that of FIG. 28 showing the
device and the cannula placement assembly including further details of
the cannula needle port cover after cannula deployment;

[0049]FIG. 30 is a sectional view, to an enlarged scale, showing a drive
needle assembly including a drive needle and drive needle head according
to a further embodiment of the invention; and

[0050]FIG. 31 is a sectional view, to an enlarged scale, illustrating an
alternative embodiment of a cannula port cover after cannula deployment.

DETAILED DESCRIPTION OF THE INVENTION

[0051]Referring now to FIGS. 1 and 2, they are perspective views of an
infusion device 110 embodying various aspects of the present invention
FIG. 1 shows the device prior to receiving and thus without a cannula
while FIG. 2 illustrates the device after having received a cannula 130
that has a distal end 131. As may be seen in both FIGS. 1 and 2, the
device 110 generally includes an enclosure 112, a base 114, a first
actuator control button 116, and a second actuator control button 118.

[0052]The enclosure 112, as will be seen subsequently, is formed by virtue
of multiple device layers being brought together. Each layer defines
various components of the device such as, for example, a reservoir, fluid
conduits, pump chambers, and valve chambers, for example. This form of
device construction results in a compact design and enables manufacturing
economy to an extent that the device is disposable after use.

[0053]The base 114 preferably includes a pad 115 attached to the base 114.
The pad 115 has an adhesive coating 117 on the side thereof opposite the
base 114 to permit the device to be adhered to a patient's skin. The
adhesive coating may originally be covered with a releasable cover 292
(FIG. 13A) that may be pealed off of the adhesive layer 117 when the
patient endeavors to adhere the device 110 to their skin.

[0054]The device 110, as will be seen herein after is first adhered to the
patient's skin followed by the deployment of the cannula 130 thereafter.
However, it is contemplated herein that various aspects of the present
invention may be realized within a device that may alternatively be mated
with a previously deployed cannula assembly.

[0055]The actuator buttons 116 and 118 are placed on opposites sides of
the device 110 and directly across from each other. This renders more
convenient the concurrent depression of the buttons when the patient
wishes to receive a dose of the liquid medicament contained within the
device 110. This arrangement also imposes substantially equal and
opposite forces on the device during dosage delivery to prevent the
device from being displaced and possibly stripped from the patient. As
will be further seen hereinafter, the concurrent depression of the
buttons is used to particular advantage. More specifically, the actuator
button 116 may serve as a valve control which, when in a first position
as shown, establishes a first fluid path between the device reservoir and
the device pump to support pump filling, and then, when in a second or
depressed position, establishes a second fluid path between the device
pump and the device outlet or distal end of the cannula to permit dosage
delivery to the patient. As will be further seen, a linkage between the
control actuator buttons 116 and 118 permits actuation of the device pump
with the actuator control button 118 only when the second fluid path has
been established by the first actuator control button 116. Hence, the
first actuator control button 116 may be considered a safety control.

[0056]The actuator buttons 116 and 118 are preferably arranged to require
a complete through of their travel to achieve activation of the device
pump and thus dosage delivery. This, together with the sudden release of
resistance to actuator advancement creates a snap action that provides an
advantage in positively knowing that dosage delivery has occurred and
that no less than a full dose has been delivered. For more description
regarding this feature, reference may be had to co-pending application
Ser. No. 11/906,102, titled DISPOSABLE INFUSION DEVICE WITH SNAP ACTION
ACTUATION, which application is owned by the assignee of this application
and is incorporated herein by reference in its entirety.

[0057]As may be noted in FIG. 1, the device 110 includes a cavity 120 that
is arranged to receive a cannula assembly 122 (FIG. 2) from which the
cannula 130 extends. When the cannula is deployed, the outlet 124 of the
device 110 is placed in fluid communication with the cannula 130 by a
cannula carrier 128 of the cannula assembly 122 that carries the cannula.
When thus deployed, the cannula 130 extends from the base 114 of the
device 110 to beneath the skin of the user.

[0058]As may further be noted in FIGS. 1 and 2, the enclosure 112 of the
device 110 includes a pair of pockets 140 and 142 on opposite sides of
the second actuator button 118. A similar pair of pockets, not seen in
the figure, are also provided on opposite sides of the first actuator
button 116. These pockets are used to receive corresponding projections
of a cannula placement assembly for releasably joining the cannula
placement assembly to the device 110 to support cannula deployment as
will be described subsequently. As will also be seen, upon cannula
deployment, the cannula placement assembly is automatically released from
the device by the driver projections being forced from the pockets.

[0059]Referring now to FIG. 3, it is an exploded perspective view of the
device 110 of FIG. 1. It shows the various component parts of the device.
The main component parts include the aforementioned device layers
including the base layer 160, a reservoir membrane 162, an intermediate
layer 164 and a top body layer 166. As may also be seen in FIG. 3, the
base layer 160 is a substantially rigid unitary structure that defines a
first reservoir portion 168, a pump chamber 170, and a valve chamber 190
that receives a shuttle bar 200 of a shuttle valve 210. A reservoir
membrane layer 162 is received over the reservoir portion 168 to form an
expandable/deflatable reservoir of the device 110. The base layer 160 may
be formed of plastic, for example. The base and the top body layer may be
joined together, trapping the intermediate layer there between by any
means such as with screws, ultrasonic welding or laser welding.

[0060]The valve chamber 190 is arranged to receive a valve shuttle bar 200
carried by and extending from the first actuator button 116. A series of
O-rings, to be described subsequently, are seated on the shuttle bar 200
to form first, second, and third valves. The actuator button 116 also
carries a first linkage portion 240 of the linkage that permits actuation
of the device pump with the actuator control button 118 only when the
second fluid path has been established by the first actuator control
button 116. The first linkage portion 240 is received within a suitably
configured bore 270 formed in the base layer 160 and will be described
subsequently.

[0061]The pump actuator button 118 is arranged to be linked to a pump
piston 300 and a second linkage portion 340 to interact with the first
linkage portion 240. The pump piston 300 is arranged to be received
within the pump chamber 170 and the second linkage portion 340 is
arranged to be received within the bore 270 for interacting with the
first linkage portion 240. O-rings are seated on the piston 300 to
provide a seal against leakage and to prevent external contaminants from
entering the piston chamber.

[0062]The intermediate layer 164 may be a generally resilient member and
received on the base layer 160 to cover channels scribed in the base
layer as a type of gasket to form fluid channels 380 that serve to
conduct the medicament from the reservoir to the device outlet and to the
distal end 131 (FIG. 2) of the cannula 130. Springs 410 are arranged to
spring load the actuator buttons 116 and 118 away from each other.

[0063]The reservoir membrane 162 is formed of flexible membrane material
and is received over the reservoir portion 168 to form the reservoir of
the device 110. A rigid plate 420 is arranged to be adhered to the
reservoir membrane 162 of the reservoir. Because the membrane 162 is
flexible, it will move as the reservoir is filled and emptied. The rigid
plate 420 will then move with it. The plate 420 includes an eyelet 422
dimensioned to receive an elongated web 424 that forms a part of a
medicament level indicator. The web 424 carries an indicator line or
feature 426 that may be read through a window 428 of the device top most
panel 440.

[0064]Another component of the device 110 is a translucent window 450 that
is received on the underside of the base 160. As will be seen
hereinafter, the window forms a part of a prime indicator. It is formed
of a transparent material such as glass or transparent plastic and has a
roughened surface rendering it translucent. However, when it is covered
with or at least wetted by liquid medicament, it is rendered essentially
transparent creating a visually obvious condition and, for example,
permitting indicia to be seen beneath it indicating that the conduit to
the device outlet is primed and ready to deliver fixed doses of
medicament when desired.

[0065]FIGS. 4-6 show details of the operation of the linkage that permits
actuation of the device pump with the actuator control button 118 only
when the second fluid path from the reservoir to the outlet has been
established by the first actuator control button 116 The linkage has been
given the general reference character 150.

[0066]As may be seen FIG. 4, the first actuator button 116 has an
extension 152 that terminates in a block 154. The block 154 has a first
ramp surface 156 and a second ramp surface 158. When the device 110 is
actuated, the button 116 is concurrently depressed with pump button 118.
It and its extension 152 and block 154 are free to move to the right. As
seen in FIGS. 4 and 5, the pump actuator button 118 has parallel
extensions 250 and 252 which are joined and separated be a rod member
254. The extensions 250 and 252 are pivotally mounted to pivot about a
pivot point 256. Another extension 260 of the pump actuator button 118
spring biases the extensions 250 and 252 as shown in FIG. 4. As seen in
FIG. 4, the extensions 250 and 252 abut an abutment 262 which they must
clear to enable the actuator 118 to be moved to the left. As shown in
FIG. 5, as the button 116 is depressed, its extension 152 moves to the
right causing the first ramp surface 156 to engage the rod member 254.
Continued movement of the button causes the rod member 254 to ride up the
first ramp surface 156 which in turn causes the extensions 250 and 252 to
begin to move slightly to the left and bend upward against the loading of
extension 260. Eventually, the rod member 254 rides up the length of the
first ramp 156 and down the second ramp 158 causing the extensions 250
and 252 to clear the abutment 262 and continue their travel to the left
until the extensions are received on the opposite side of the abutment as
shown in FIG. 6. The pump button 116 has now been fully depressed to
deliver a dose of measured medicament. When the ends of extensions 250
and 252 totally clear the abutment 262, they will snap behind the
abutment 262 as shown in FIG. 6 and become temporarily locked. Meanwhile,
the rod member 254 has traversed all the way down the second ramp surface
158. The buttons 116 and 118 are now fully depressed.

[0067]Hence, from the above, it may be seen that the pump button 118 could
not at first move freely while the first actuator button 116 which
operates the valves could. As a result, the pump actuation lags behind
the valve actuation. This enables the device outlet to be sealed from the
reservoir and the pump connected to the outlet before the pump is
permitted to pump any medicament to the outlet. Hence, the device
establishes a medicament delivery flow path to the cannula before the
pump is able to begin pumping the medicament to the patient. Thus, it is
assured that there is never an open unobstructed pathway between the
reservoir and the fluid outlet. Also, by assuring that the pump only
draws fluid from the reservoir when the pathway to the outlet is sealed
off, it is also assured that a precise amount of fluid is moved with each
pump cycle. This operation is completely timed by the linkage just
described and occurs quickly, appearing to the patient that both actuator
buttons are moving at the same rate.

[0068]When the extensions 250 and 252 of the pump button clear the
abutment 262, they become locked in a snap action. This provides positive
feedback to the patient that a dosage of medicament was delivered as
desired. It also causes a full dose to be delivered. By virtue of the
snap action of the pump actuator, only full doses may be administered.

[0069]When the medicament has been delivered, the spring loading of the
actuator buttons returns the buttons to their first or initial position.
During this time, the same timing provided by the block 154 is used for
recharging the pump. More specifically, ramp 158 unlatches the ends of
extensions 250 and 252 by lifting rod member 254. While the extensions
250 and 252 are being lifted by the ramp 158, the valve control button
116 is returning to the left to cause the outlet to be disconnected from
the pump before the reservoir is reconnected to the pump for charging,
thus sealing the outlet from both the pump and the reservoir before the
reservoir is connected to the pump for recharging. This assures that the
pump does not pull medicament from the patient but only from the
reservoir. As the pump returns, a full dose of the medicament is drawn up
into the piston chamber 170 to ready the device for the next dosage
delivery.

[0070]Referring now to FIGS. 7 and 8, they are schematic representations
of the valves and pump of the device of FIG. 1 between medicament dosage
filling (FIG. 7) and medicament dosage delivery (FIG. 8) As may be seen
in FIGS. 7 and 8, the device 110 further includes a reservoir 222, a pump
224, and the cannula 130. The reservoir 222 may be formed as shown in
FIG. 3 by the combination of the device base 160 and the flexible
membrane 162. The device further includes the shuttle valve 210 including
shuttle bar 200. The shuttle bar 200 is shown within the valve chamber
190. The shuttle bar 200 and O-rings 214 and 216 form a first valve 212,
shuttle bar 200 and O-rings 220 and 222 form a second valve 234 and
shuttle bar 200, O-ring 226 and a bypass channel 186 form a third valve
224. Although O-rings are used herein to form seals, other types of valve
construction may employ forms of seals other than O-rings without
departing from the invention.

[0071]The pump piston 300 is within the piston camber 170 to form a piston
pump 172. The actuator control button 218 is directly coupled to and is
an extension of the pump piston 226. It may also be noted that the
actuator buttons 116 and 118 are spring loaded by springs 117 and 119,
respectively. The springs are provided for returning the actuator buttons
to a first or start position after a dosage is administered.

[0072]A fluid conduit 182 extends between the reservoir 180 and the valve
212. An annular conduit 192 extends between the O-rings 216 and 226, and
an annular conduit 194 extends between the O-rings 226 and 220. A fluid
conduit 184 provides a fluid connection between the reservoir 180 and the
annular conduits 192 and 194 depending upon the position of the shuttle
valve 210. Also illustrated in FIG. 7 is the linkage 150 that assures
that the shuttle valve 210 is actuated before the piston pump 172 is
actuated to provide a dose of medicament.

[0073]In FIG. 7, the valves are shown in a first configuration immediately
after having returned to their first position following a dosage
delivery. After the return of the valves, the linkage 150 permits the
pump actuator 118 and piston 300 to return for refilling the pump chamber
300 in ready for the next medicament dosage delivery. During their
return, the medicament flows as indicated by arrows 202 from the
reservoir 180, through the conduit 182, through the annular channel 192,
through conduit 184, and into the pump chamber 170.

[0074]As may be noted, when in the first position, the valves 218 and 224
isolate the outlet 124 from both the reservoir 180 and the piston pump
118. Having two such valves isolate the outlet 124 when the valves are in
the first configuration provides an added degree of safety from
medicament being inadvertently delivered to the patient between dosage
deliveries. For example, this provides additional safety that the liquid
medicament is not accidentally administered to the patient
notwithstanding the inadvertent application of pressure to the reservoir
In applications such as this, it is not uncommon for the reservoir to be
formed of flexible material. While this has its advantages, it does
present the risk that the reservoir may be accidentally squeezed as it is
worn. Because the valves 118 and 124 isolate the outlet 124 when the
valves are in their first configuration, this redundant protection
assures that pressure, accidentally applied to the reservoir, will not
cause the fluid medicament to flow to the cannula.

[0075]In addition to the linkage 150 preventing return of the piston 300
until after the valves return to their first and start positions, the
O-rings on the shuttle bar 200 are also spaced apart to insure that the
valves 218 and 224 isolate the outlet 124 from the pump 172 and reservoir
180 before the pump is again connected to the reservoir. The O-ring
spacing thus effectively forms a second linkage to assure that the
cannula 130 is connected to the pump 172 only when a dosage is to be
delivered and that it is never connected to the reservoir 180.

[0076]In operation, the pump chamber 170 is first filled as the actuator
button 118 returns to the first position after having just delivered a
medicament dosage. In this state, the shuttle valve 210 is set so that
the first valve 212 will be open and the second and third valves 218 and
224 will be closed. This establishes a first fluid path indicated by
arrows 202 from the reservoir 180 to the pump chamber 170 to fill the
piston pump 172. When the patient wishes to receive another dose of
medicament, the actuator buttons are concurrently pressed. The
aforementioned linkages, including linkage 150, cause the first valve 212
to close and the second and third valves 218 and 224 to thereafter open.
Meanwhile, actuation of the pump 172 is precluded until the first valve
212 is closed and the second and third valves 118 and 224 are opened. At
this point a second fluid path indicated by arrows 204 is established
from the pump chamber 170 to the cannula 130. The medicament is then
administered to the patient through the distal end 131 of cannula 130.

[0077]Once the medication dosage is administered, the piston 330, and thus
the actuator button 118, is returned under the spring pressure of spring
119 to its initial position. During the travel of the piston back to its
first position, a given volume of the liquid medicament for the next
dosage delivery is drawn from the reservoir into the pump chamber 170 as
described above to ready the device for its next dosage delivery.

[0078]Referring now to FIG. 9, it is a sectional view in perspective
showing the valve configuration of the device 110 of FIG. 1 during
medicament filling of the pump chamber 170 immediately after a dosage
delivery. Here, it may be clearly seen that the first actuator button 116
is directly coupled to the shuttle bar 200 of the valves 212, 218, and
224. Above the valves are the conduits from the reservoir, from the pump,
and to the cannula. More particularly, the conduit 182 is in fluid
communication with the reservoir, the conduit 184 is in fluid
communication with the pump, and the conduit 124 is in fluid
communication with the cannula. The valves are shown with the first valve
212 opened, communicating reservoir conduit 182 with the pump conduit 184
through channel 192, the second valve 218 closed and blocking the conduit
124 to the cannula, and the third valve 224 closed and blocking both the
reservoir conduit 182 and the pump conduit 184 from the cannula conduit
124. This permits medicament to flow from the reservoir through conduit
182, through channel 192, and to the pump chamber 170 through conduit 184
as the actuator button 116 returns to its first position. Hence, the pump
chamber is filled and ready for the next dosage delivery.

[0079]Referring now to FIG. 10, it is a sectional view in perspective
similar to that of FIG. 9 but showing the valve configuration of the
device 110 of FIG. 1 during medicament delivery. Here, the valves are
shown with the first valve 212 closed and blocking the reservoir conduit
182, the second valve 218 opened permitting the outlet conduit 124 to
communicate with the annular conduit 194, and the third valve 224 opened
permitting medicament to flow from the annular conduit 192, through
bypass 186, and to annular conduit 194. Thus, medicament is permitted to
flow from the pump conduit 184, through annular conduit 192, through the
bypass 186, through annular conduit 194, and into the outlet conduit 124
to administer the fixed volume dosage. As previously mentioned, the
O-rings defining the first valve 212, the third valve 224, and the second
valve 218 are spaced apart so that conduit 182 is blocked before conduits
184 and 124 are connected together through the valves 224 and 218.

[0080]FIG. 11 is a top perspective view of the base 160 of the device 110
of FIG. 1. Carried on the base 160 is the intermediate layer 164.
Together, the base 160 and intermediate layer 164 define numerous fluid
conduits within the device 110. One such fluid conduit is designated with
reference character 270 in FIG. 11. The conduit 270 is within the fluid
path that leads to the outlet 124. It is in the downstream portion of
that path and takes a bend at 272 towards the bottom side of the base 160
where it, through an opening 274, enters a chamber 276 (FIG. 12). The
chamber 276 communicates with the device outlet 124 that projects into
the aforementioned cavity 120. When the cannula 130 (FIG. 13) is placed,
it extends through an opening 123 in the cavity to beneath the patient's
skin and communicates with the outlet 124 as described herein after.

[0081]The chamber 276 is partly defined by a seal rim 278 which receives a
translucent cover 280 (FIG. 13). The top wall of the chamber 276 has an
inverted cone shaped surface 282 portion and a tapered portion 284 to the
outlet 124.

[0082]The translucent cover may be formed of transparent plastic wherein
the surface that faces the chamber is roughed in a manner that renders
the plastic cover translucent. The upper surface of the chamber is
preferably coated with indicia which may, for example, be a color, such
as blue. When the chamber is empty, the blue indicia will not be readily
seen because the rough surface of the cover has rendered the cover
translucent. However, when the chamber 276 is filled with a liquid, such
as the liquid medicament, the cover 280 will become more transparent
allowing the blue indicia to be readily seen. The chamber 276 and cover
280 thus form a prime indicator 286 adjacent the outlet 124. More
particularly, the prime indicator 286 is immediately adjacent the outlet
124 since when the chamber is filled and the indicia readily seen, it
will be known that the conduits and cannula are sufficiently prime with
medicament to permit a full dosage to be delivered upon the next
activation of the device 110.

[0083]In use, it is contemplated that the reservoir be filled through a
fill port 290 on the bottom of the device 110 before the device is
deployed on the patient's skin. After the device is filled, the
translucent cover or window 280 may be viewed during device priming.
During the priming process, the actuators 116 and 118 may be depressed a
number of times until the blue indicia on the top surface portions 282
and 284 of the chamber are seen through the window 280. This provides an
indication to the user that the chamber 276, and more importantly, the
conduits are sufficiently primed and full with medicament to enable
actual dosage delivery upon the next actuation of the device 110. Hence,
a prime indicator 286 is provided immediately adjacent the outlet 124.

[0084]In FIG. 13A, it may be seen that the removable non-adhesive layer
292, in accordance with this embodiment, includes two portions, a first
portion 293 and a second portion 294. Each of the first and second layer
portions 293 and 294, respectively, includes a tab 298 and 297
respectively that extend beyond the margins of the device base. This
permits the tabs 297 and 298 to be grasped for effortless removal of the
removable non-adhesive layer portion 294 and 293. The layer portion 293
includes cutouts. The cutouts 295 and 296 extend through the pad 115
(FIG. 2) to provide access to the device fill port 290 and the prime
indicator window 280. Hence, as described above, the device 110 may be
filled and primed for use before the removable layer portions 293 and 294
are removed for adhering the device to a patient's skin.

[0085]FIGS. 14-16 are sectional views in perspective of an occlusion
detector and lock-out 350 according to an embodiment of the device of
FIG. 1. FIG. 14 shows the occlusion detector and lock-out 350 prior to an
intended dosage delivery, FIG. 15 shows the occlusion detector and
lock-out 350 during to an intended dosage delivery, and FIG. 16 shows the
occlusion detector and lock-out 350 during occlusion detection and just
prior to lock-out.

[0086]The occlusion detector and lock-out 350 serves to detect, during
each dosage delivery, blockages between the shuttle valve and the distal
end 131 of the cannula 130 (FIG. 8). Such blockages are most likely to
occur within the cannula and may result in an improper amount of
medicament being delivered during an attempted dosage delivery. For
example, the user might have an erroneous belief that a full dosage had
been delivered when, in fact, a dosage of insufficient quantity had been
delivered. As will be seen subsequently, the occlusion detector is
responsive to pressure within the pathway from the shuttle valve to the
outlet and cannula that occurs during an attempted dosage delivery when a
blockage exists.

[0087]The occlusion detector 350 has an inlet 132 that communicates with
the outlet 124 (FIG. 10) of the shuttle valve 210 and an outlet 134 that
communicates with the prime indicator 286 (FIG. 12). Between the inlet
132 and the outlet 134 is a channel 136. Hence, the channel 136 is within
the fluid path from the valve to the outlet 125 of the device that may be
coupled to the cannula 130 (FIGS. 7 and 8). The occlusion detector 350
also includes a resilient diaphragm 352 over which the channel 136
extends. Adjacent the diaphragm 352 is a deflectable stop 354. As will be
seen subsequently, when there is an occlusion within the fluid path, an
attempted dosage delivery results in an increased back pressure against
the diaphragm 352 and the deflectable stop 354. This causes the
deflectable stop 354 to engage a projection 157 of the linkage 150. This
disables the linkage 150 that controls the interaction of the actuator
buttons 116 and 118 and that causes the actuator buttons 116 and 118 to
become locked.

[0088]More particularly, as may be further seen in FIG. 14, the linkage
150 is adjacent the occlusion detector 350. When the actuator buttons are
depressed, the projection 157, carried by the extension 152 of the valve
actuator button 116, slides across block 255 carried on pivot 256.

[0089]As may be seen in FIG. 15, upon further depression of buttons 116
and 118, the projection 157 slides past the distal end of the deflectable
stop 354. It may also be seen that, as previously described, the rod
member 254 has ridden up the first ramp 156 and down the second ramp 158
of block 154. This causes the first ramp 156 to engage a ramp surface 257
of block 255.

[0090]If no occlusion exists within the fluid path to the cannula, the
blocks 154 and 255 and the actuator buttons 116 and 118 will return as
previously described under spring pressure. However, if an occlusion does
exist within the fluid path to the cannula, back pressure will quickly
build in the channel 136 to cause the deflectable stop 354 to be
deflected downwardly. This is shown in FIG. 16. The deflectable stop 354
is now aligned with the projection 157. When, under spring pressure, the
actuator buttons 116 and 118 are urged to their starting positions, the
projection 157 will be caught by the deflectable stop 354 to lock the
device and preclude its further use. Still further, the deflectable stop
354 or the projection 157 may be breakable or permanently deformable upon
their engagement. This would render the linkage 150 jammed and
irreversibly locked to permanently preclude further use of the device.

[0091]Referring now to FIG. 17, it is a perspective view of the device 110
of FIG. 1 with a cannula placement assembly 500 releasably attached
thereto ready to provide the device with a cannula according to a still
another embodiment. It is contemplated that the device 110 and cannula
placement assembly 500 be pre-attached to each other upon delivery to a
patient and that upon placement of the cannula, the cannula placement
assembly 500 be automatically separated from the device 110.

[0092]The cannula placement assembly 500 generally includes a cannula
driver portion 510 and an actuation portion 512. The cannula driver
portion 510 is generally cylindrical in shape including a drive cylinder
514. The actuation portion includes an actuator button 516 and a safety
control button 518. As will be seen subsequently, the safety control
button 518 must first be depressed into a locked depressed position
before the actuator button 516 may be depressed to set the cannula
placement sequence into motion.

[0093]FIG. 18 is a sectional view, in perspective, to an enlarged scale,
of the device 110 and cannula placement assembly 500 before the cannula
is deployed. As may be noted in FIG. 18, the interior components of the
cannula driver portion 510 includes a plunger 524, a needle assembly 520,
and the cannula assembly 122.

[0094]The cannula assembly, as previously described, includes the cannula
130, of the type known in the art, and a cannula carrier 128. The cannula
carrier 128 is arranged to be received within the cavity 120 into which
the device outlet 124 projects. Once the cannula carrier 128 is received
into the cavity 120, the cannula carrier 128 establishes a fluid path
from the outlet 124 to the cannula 130.

[0095]The needle assembly 520 includes a drive needle 522. The drive
needle 522 includes a needle head assembly 526 and a needle shaft 527.
Before the cannula 130 is placed, the cannula assembly 122 is carried by
the needle assembly 520 and more specifically, by the cannula 130 being
received on the drive needle 522 with the cannula carrier 128 being
immediately adjacent the drive plunger 524 as shown.

[0096]The needle head assembly 526 is initially seated within the drive
plunger 524. To that end, the needle head assembly 526 is within the
plunger 524 and has an exterior surface 530 that conforms to the interior
surface 532 of a wall portion 531 of the plunger 524. The needle shaft
527 extends from the needle head assembly 526, through an opening of the
plunger 524, through the cannula carrier 128, and finally through the
cannula 130 to terminate at a tip 521. During cannula placement, the
cannula 130 and drive needle 522 extend through the opening 123 of the
device 110.

[0097]The cannula driver 510 further includes a first drive spring 534 and
a second drive spring 536. The first drive spring is originally
compressed between an inner end wall 538 of the drive cylinder 514 and a
top surface 540 of the plunger 524. The first drive spring 534 serves to
drive the plunger 524 downwardly to in turn drive the cannula 130 and the
drive needle 522 through the opening 123.

[0098]The plunger 524 is released by the actuator button 516 being
depressed. As will be seen subsequently, the actuator button 516 includes
a portion that interferes with a shoulder of the plunger 524. When the
actuator button is depressed, that interference is resolved and the drive
carrier 524 is free to move downwardly under the influence of the first
drive spring 534. The needle tip 521 pierces the patient's skin and the
lower portion of the needle shaft 527 and cannula 130 are placed beneath
the patient's skin. The cannula 130 and needle 522 quickly reach the
fully driven, temporary, configuration shown in FIG. 19.

[0099]In FIG. 19, it may be seen that the cannula 130 and needle shaft 527
upon which the cannula 130 is carried have been driven through the
opening 123 of the device 110. The first drive spring 534 is now in an
extended condition.

[0100]When the cannula driver 510 reaches the configuration shown in FIG.
19, the wall portion 531 of the plunger 524 clears a shoulder 542 of a
short wall portion 544 of the drive cylinder 514. The wall portion 531
springs outwardly separating the conformal surfaces 530 and 532 of the
wall portion 531 and the needle head 526, respectively. This frees the
needle head 526 from the plunger 524. The needle head 526 is now free to
move upwardly out of and away from the plunger 524 under the influence of
the second drive spring 536.

[0101]As the needle head 526 moves upwardly, it of course takes the needle
shaft 527 with it. When the needle head 526 reaches the extent of its
travel (FIG. 20) by the extension of the second drive spring 536 (the
first drive spring 534 has been omitted from the figure for clarity), the
needle shaft 527 is fully extracted from the cannula 130 leaving only the
cannula 130 beneath the patient's skin. The cannula carrier 128 has also
been received within the cavity 120 of the device 110. As the cannula
carrier 128 is received within the cavity 120, the device outlet 124 is
placed into fluid communication with the cannula 130 through the cannula
carrier 128.

[0102]FIG. 21 is a sectional view, in perspective, showing details of the
actuator portion 512 of the cannula placement assembly 500 of FIG. 17, as
configured prior to cannula deployment. As previously described, the
actuator portion 512 includes the safety control button 518 and the
actuator 516.

[0103]The safety control button includes a recess 550 and the actuator
button 516 includes an extension 560. Before actuation, the extension 560
of the actuator 516 abuts the safety control button to preclude the
depressing of the actuator 516. However, when the safety control button
is depressed, as will be seen subsequently, the recess 550 is brought
into alignment with the extension 560 to permit the actuator 516 to be
depressed for setting into motion the placement of the cannula 130 as
previously described.

[0104]As may also be noted in FIG. 21, the cannula placement assembly 500
further includes a plurality of projections 562 and 564. It is also
contemplated that the cannula placement assembly 500 includes two
additional such projections. The projections are arranged to be received
within corresponding pockets of the wearable infusion device to permit
the cannula placement assembly 500 to be releasably carried on the device
110 as shown, for example, in FIG. 17. For example, projection 562 is
intended to be received by pocket 140 of the device 110 of FIGS. 1 and 2.
The distance between the projections 562 and 564 is maintained by a latch
566 that includes a bendable arm 568 and a catch 572. The bendable arm
includes a hook 570 at its distal end that is held by the catch 572. At
least one urging member in the form of springs 573 and 575 (FIG. 20)
serve to provide a continuous force for separating the projections 562
and 564. That force also maintains the hook 570 locked onto the catch
572, and the hook 570 being locked onto the catch 572 maintains the
projections within their respective pockets to releasably maintain the
cannula placement assembly 500 on the device 110.

[0105]The actuator 516 still further includes a latch release projection
580. The latch release projection 580 includes a ramped surface 582
arranged to engage and bend the bendable arm 568 as the actuator 516 is
depressed. Eventually, sufficient depression of the actuator 516 bends
the arm 568 sufficiently to cause the hook 570 to clear the catch 572.
The actuator is shaped in such a manner that, as it is depressed in a
single motion, it causes release and placement of the cannula before the
hook 570 clears the catch 572. When the hook 570 clears the catch 572,
the latch 566 is released and the projections, including projections 562
and 564 are forced apart under spring pressure to cause the cannula
placement assembly 500 to be separated from the device 110.

[0106]FIG. 22 is a sectional view, in perspective, and to an enlarged
scale, of the cannula placement assembly of FIG. 17, showing the assembly
through a plane perpendicular to the sectional plane of FIG. 21 and prior
to cannula deployment. Here it may be seen that the control button 518
includes a pair of chordal recesses 580 and 582 that defined bendable
legs 584 and 586 respectively. Each of the legs 584 and 586 includes a
projecting foot 588 and 590 respectively. When the safety control button
518 is in a raised initial position as shown in FIG. 22, the foot 588 is
confined within a slot 592 of an extension 598 of the actuator button 516
and the foot 590 is confined within a slot 594 of another extension 598
of the actuator button 516.

[0107]When the control button 518 is depressed, the legs 580 and 586
permit the feet 588 and 590 to slide out of their respective slots 592
and 594, respectively. They then progress downwardly until the legs 584
and 586 and feet 588 and 590 wrap about the extensions 596 and 598 of the
actuator 516. The feet 588 and 590 become confined beneath bottom
surfaces 600 and 602, respectively, of the actuator button extensions 596
and 598, respectively to lock the safety control 518 in the enable
configuration of FIG. 23.

[0108]In FIG. 23 it may be clearly seen that the feet 588 and 590 are
beneath and confined by the bottom surfaces 600 and 602, respectfully, of
the actuator button extensions 596 and 598. The bendable legs 584 and 586
cause the control button 516 to enter this configuration with a snap
action. This provides positive feedback to the user that the control
button has been successfully depressed and that the cannula placement
assembly is now ready for the depression of the actuator button 516. The
confinement by the actuator extensions 596 and 598 of the feet 588 and
590 causes the control button 518 to be locked in the depressed enable
state. This conveys to a user after use that the cannula placement
assembly is not to be reused and even assists in making such reuse
impossible or at least difficult.

[0109]With the control button now depressed and engaged in the enable
configuration, the extension 560 of the actuator button 516 (FIG. 21)
will now be aligned with the slot 550 of the control button 518. This
permits the actuator to be depressed and actuated.

[0110]FIGS. 24 and 25 are sectional views showing the cannula placement
assembly 500 as the actuator button 516 is being depressed. In FIG. 25 it
may be seen that the extension 560 of the actuator button 516 is aligned
with and entering into the slot 550 of the control button 518. As this
occurs, the extension 598 slides in the chordal recess 582 of the control
button 518 and the extension 596 slides in the chordal recess 580 of the
control button.

[0111]The extension 598 further includes a wing 610 having an upper
surface 612 that normally engages a lower surface 523 of the plunger 524
to interfere with the movement of the plunger 524 as previously
described. As the actuator button 516 is depressed, the upper surface 612
of the extension 598 clears the lower surface 523 of the plunger 524.
When this occurs, the drive carrier is released to be driven by spring
534 for placing the cannula 130 into a deployed position beneath the
patient's skin.

[0112]FIG. 25 further shows that the latch 566 includes a second catch
573. The second catch 573 serves to catch the hook after it is lifted
over the first catch 772. The second catch 573 is also positioned so that
even though it catches the hook 570, the projections are still separated
sufficiently to release the cannula placement assembly 500 from the
device 110. The cannula placement assembly will not fall apart because it
is held together in part by the second catch 572 catching the hook 570.

[0113]FIG. 26 is a sectional view showing the cannula placement assembly
500 after cannula deployment. The assembly is separated from the device.
The projection 560 is fully within the slot 550 of the control button
518. This serves to further preclude reuse of the assembly 500 after
cannula placement.

[0114]FIG. 27 is a perspective view of the device 110 and cannula
placement assembly 500 after cannula deployment and separation of the
cannula placement assembly from the device. Clearly seen in FIG. 27 are
the remaining projections 563 and 565 and remaining pockets 141 and 143
for releasably retaining the assembly 500 on the device 110. After
cannula placement, the separated cannula placement assembly 500 may be
disgarded.

[0115]FIG. 28 is a sectional view of the cannula placement assembly 500
and the device 110 to an enlarged scale showing details of a cannula
needle port cover 125 during delivery of the cannula 130. The cannula 130
is carried on the cannula carrier 128. The cannula carrier includes a
port 127 through which the needle 522 passes when it is retracted back
into the driver 510 by the spring 536. To preclude access into the device
and especially direct access to the cannula through the port 127 after
the cannula 130 has been deployed, the cannula carrier 128 includes the
port cover 125. In accordance with this embodiment, the port cover is
made of relatively impenetrable material such as hard plastic or steel or
the like and is substantially U-shaped and is confined within a slot 129.
One leg of the port cover 125 is displaced and held away from the port
127 by the needle 522. It is a resilient material, such as spring steel
and is held in place in, for example, a slightly compressed state, by the
needle shaft 527 which is loaded through the hole in the port cover as
shown at 125 in FIG. 28. Responsive to the cannula 130 being placed and
the needle shaft 527 removed from the device 110, the one leg of the port
cover is freed and permitted to spring to its natural shape such that the
one leg overlies the port 127 as shown at 125 in FIG. 29 and in greater
detail at 727 in FIG. 31. This results in the port 127 being blocked to
preclude access to the interior of the device 110 once the cannula has
been placed. Once the cannula 130 is deployed, the device 110 will appear
as shown in FIG. 2. As previously mentioned, when the cannula 130 is
placed, a fluid connection is established between the outlet 124 and the
cannula 130 through the cannula carrier 128. After priming, the device
110 is ready to deliver its first dose of medicament.

[0116]FIG. 30 is a sectional view, to an enlarged scale, showing another
driver needle assembly 620 including a drive needle shaft 622 and drive
needle head 626 according to a further embodiment of the invention. Here
it may be seen that the drive needle shaft 622 and the drive needle head
626 are two separate parts. The drive needle shaft 622 has a turned
section 623 and an elongated section 627. The turned section 623 rides in
a slot 630 of the drive needle head 626. The elongated section 627 passes
through and is free to slide on a through bore 628 of the drive needle
head 626. The needle assembly 620 may be used to assist in cannula
placement and returned by spring 536 after cannula deployment in the same
manner as previously described.

[0117]FIG. 31 is a sectional view, to an enlarged scale, illustrating an
alternative embodiment of a cannula port cover 725. The port cover is
shown covering a needle port 727 after cannula deployment. The port 727,
as in the precious embodiment, is defined by the cannula carrier 728. The
port cover 725 is generally U-shaped and confined in a cut-out 730. The
cut-out 730 has a width that is greater than the diameter of the needle
slot 727 to permit a cannula driver needle (not shown) to pass there
through upon return after cannula placement. The port cover 725 has an
end 729 that is confined by the cut-out 730 and a slot 732 formed in a
side wall of the cannula carrier 728. The port cover 725 is therefore
free to pivot to the position shown after the cannula driver needle (not
shown) passes there through upon its return.

[0118]As may be noted in FIG. 31, the port cover 725 has a width, adjacent
the port 727, that is smaller than the diameter of the port 727. While
the port cover 725 does not completely cover the port 727, it is still of
sufficient dimension to block the port 727 and preclude access to the
cannula through the port 727 by, for example, an external syringe needle.

[0119]While particular embodiments of the present invention have been
shown and described, modifications may be made. It is therefore intended
in the appended claims to cover all such changes and modifications which
fall within the true spirit and scope of the invention as defined by
those claims.